Molecules: You'd better learn to live with them.
Ion-exchange resins are surprisingly simple things - here's the idea: just about everything that has a charge has to have an opposite charge around somewhere. Ususally, charged things float around willy-nilly in solution (your Na+ and Cl- in your salt, for example). If you have something insoluble, like a plastic, that will carry a charge, it will always have some intimately associated neighbors of opposite charge. This can slowly (or rapidly) exchange its charged neighbors with its environment, depending on solution conditions. Enter amberlite IRP64.
Say you're addicted to some form of nicotine. Nicotine is positively charged. We can use a negatively charged anion exchange resin to bind positively charged nicotine cation, which will very slowly exchange for positively charged protons, or sodium cations, etc, in your mouth, and you've got time-release orally-dosed nicotine. A little better than any alternative form, too.
You've seen nicotine bound to Amberlite IRP64 sold as nicotine polacrilex - better known as nicotine gum.
Comments
I'll always remember ion-exchange resins from Arthur C Clarke's "Tales From the White Hart" where there is scene of a millionaire chemist tooling around the Caribean in a yacht pulling Uranium out of seawater using some odd variation of - ion-exchange resins. That was the kind of rich and famous I always wanted top be.
Posted by: Markk | May 15, 2007 8:52 AM
Given beads of a strong cation exchanger resin (e.g, sulfonic acid) in its H+ form and strong anion exchanger (e.g., quaternary ammonium) in its 0H- form. Mix 1:1 by charge and wait. How much electrostatic force will accrue between the beads? What about after removing water by lyophilization then azeotropic distillation?
Posted by: Uncle Al | May 15, 2007 1:11 PM
I don't have an answer to Uncle Al's question, though I do have one of my own. What if one were to chew nicotine gum with a strong base? Would the free-base nicotine be released and therefore ruin the time-release factor? Or, what if you added an acid? Would the resin be protonated and therefore release the nicotine? Ideas anyone?
Posted by: Vince Noir | May 16, 2007 1:14 AM